This proposal seeks funding to conduct experiments to measure the pain reaction of dysmenorrheic (women who experience pain with menstruation) and pregnant women. This work represents a continuation of a project funded by NIH (1 R03 MH31523-01A1) in which the pain sensitivities of women were found to differ from men and women taking oral contraceptive pills during ovulation. We would like to extend our observations to include two special groups of women who demonstrate unusual pain reactions. In the first experiment we will be systematically exploring the relationship between the presence of primary dysmenorrhea and sensitivity to pain to determine if a relationship exists and if so, whether it can be located within specific phases of the menstrual cycle. In the second experiment a women's pain reactions to radiant heat stimuli will be tested during the course of her pregnancy to determine if proximity to parturition is associated with a change in pain sensitivity. A receiver Operating Characteristic (ROC) analysis will be used in both experiments to assess the degree to which the changes in pain perception between groups and within a group over time are a result of sensory changes in pain perception or occur because the women become more or less willing to report pain. These findings could potentially add to our basic understanding of pain reactions in women and in addition contribute practically to attempts to assist women in learning to deal with their pain reactions.